A chemical sunscreen agent that's very oil soluble and requires relatively low concentrations to achieve high SPF values (it gives an SPF 12.5 at the max allowed concentration of 10%). It protects in the UVB and UVA II range (but not in UVA I) with a peak protection at 310 nm. It's particularly suitable for water-repellent and water-resistant formulations.
Regarding photostability, Diethylhexyl Butamido Triazone is super photostable. It looses 10% of its SPF protection abilities only in 25 (!!) hours when 2 hours counts already as "photostable" in the world of chemical sunscreens.
Btw, it is not a FDA-approved sunscreen agent, so you will not find it in sunscreens coming from the US. It's allowed up to 10% in Europe and up to 5% in Japan.
Show me some proof
- Pharmazie 62: 449–452 (2007), Study of the efficacy of 18 sun filters authorized in European Union tested in vitro
- Couteau, Céline, et al. "Study of the photostability of 18 sunscreens in creams by measuring the SPF in vitro." Journal of pharmaceutical and biomedical analysis 44.1 (2007): 270-273.